Methods for casting articles are well known to those skilled in the art. Current attempts to cast an article having a complex shape, however, are not practical. For example, one such known method is described in U.S. Pat. No. 4,694,879. In U.S. Pat. No. 4,694,879, a casting process that uses gasifiable parts located on a reusable part is described. The gasifiable parts are alleged to enable parts to be cast with contours that would otherwise be difficult to produce by known casting methods. The reusable part, with the gasifiable part initially located thereon, is located in a packed sand mold and then removed. The sand takes on the shape of the reusable part and the gasifiable part remains behind in the sand mold. As liquid material is added to the sand mold, it destroys the gasifiable part and fills the void it left behind. The liquid material hardens in a desired shape of the part.
The method described above may be adequate to produce a part with a limited number of non-standard contours, however, the high cost and low efficiency associated with using gasifiable parts is likely prohibitive for large scale production. Furthermore, the above-described process may be limited in shapes and the types of parts that can be produced.
Other than the method described above, the known casting methods are disadvantageous since they are limited to relatively simple shapes and designs for the parts. This is primarily because those skilled in the art know that, in a parting line system, the mold impression of a complex shape having a negative draw will crumble when it is unsupported. The crumbled mold impression cannot be used later in the process.
In light of the disadvantages in the prior art, it would be advantageous to have a method for casting complexly shaped parts having a negative draw, or parts having a complex shape associated with them, in a cost effective and efficient manner.